I believe C&C Generals is protected with Safedisk 2.8
You can try using
Alcohol 120% to copy it using it's Safedisk 2 profile. You will also need to consider the ATIP protection. This means that you cannot play the game from a cd-writer unless you use the feature "Hide CD-R Media" in the Alcohol tray icon.
If you cannot make a 1:1 copy with Alcohol, then you can copy the files to your hard drive, add the appropriate crack (download it from GameCopyWorld) and then burn back to cd-r using the same cd-label.
To apply a crack, install the game then copy over the cracked exe to the game's folder. (It's best to make a backup of the original exe before you replace it.)
When you download a crack from GCW, it will normally be in RAR format. This is a compression format somewhat like a zip file. Download Winrar 3 to open the file and extract the cracked exe.